Multilocus phylogenetic analysis and morphological data reveal a new species composition of the genusDrepanocephalusDietz, 1909 (Digenea: Echinostomatidae), parasites of fish-eating birds in the Americas

Abstract

Members of the genus Drepanocephalus are endoparasites of fish-eating birds of the families Phalacrocoracidae and Sulidae distributed across the Americas. Currently, Drepanocephalus contains three species, i.e. D. spathans (type species), D. olivaceus and D. auritus. Two additional species, D. parvicephalus and D. mexicanus were transferred to the genus Petasiger. In the current study, available DNA sequences of D. spathans, D. auritus and Drepanocephalus sp., were aligned with newly generated sequences of D. spathans and Petasiger mexicanus. Phylogenetic analyses inferred with three nuclear (LSU, SSU and ITS1, 5.8S, ITS2) and two mitochondrial (cox1, nad1) molecular markers showed that the sequences of D. spathans and D. auritus are nested together in a single clade with very low genetic divergence, with Petasiger mexicanus as its sister species. Additionally, P. mexicanus was not a close relative of other members of the genus Petasiger, showing that P. mexicanus actually belongs to the genus Drepanocephalus, suggesting the need to re-allocate Petasiger mexicanus back into the genus Drepanocephalus, as D. mexicanus. Morphological observations of the newly sampled individuals of D. spathans showed that the position of the testes is variable and testes might be contiguous or widely separated, which is one of the main diagnostic traits for D. auritus. Our results suggest that D. auritus might be considered a synonym of D. spathans and, as a result, the latter represents a species with a wide geographic range across the Americas, parasitizing both the Neotropical and the double-crested cormorant in Argentina, Brazil, Paraguay, Venezuela, Colombia, Mexico, USA and Canada.

Echinostoma chankensis nom. nov., other Echinostoma spp. and Isthmiophora hortensis in East Asia: morphology, molecular data and phylogeny within Echinostomatidae

“…These findings are supported by the study of Hernandez-Cruz et al . (2017) who, based on the absence of morphological differences between D. spathans and D. auritus, as well as their molecular similarity based on nuclear and mitochondrial markers, proposed the consideration of D. auritus as a synonym of D. spathans . However, it is not excluded that the assumption about the validity of these species will be confirmed if new data are obtained, namely, the morphology of developmental stages, as well as the sequences of the cox1 gene.…”

A fine‐scale phylogenetic assessment of digenean trematodes in central Alberta reveals we have yet to uncover their total diversity

“…Both samples from this study came from H. trivolvis snails, which match with other records of specimens derived from planorbid snails in different geographical regions, specifically the United States and Brazil (Table 3). Recent work has revealed the synonymy of D. auritus with Drepanocephalus spathans, with spathans as the chosen name (Hernández-Cruz, Hernández-Orts, Sereno-Uribe, Pérez-Ponce de León, & García-Varela, 2018). Therefore, we have identified our sequences according to this.…”

“…Furthermore, larval and immature endoparasites often lack reproductive structures used to identify their adult counterparts. Both of these problems are common among helminths (Jensen & Bullard, ; Roeber, Jex, & Gasser, ; Schell, ). Additionally, the revelation of cryptic species is becoming more common, as molecular methods expose diversity not identifiable by traditional, morphological methods (Detwiler, Bos, & Minchella, ; Detwiler, Zajac, Minchella, & Belden, ; Georgieva, Selbach et al, ; Herrmann, Poulin, Keeney, & Blasco‐Costa, ; Locke, McLaughlin, Dayanandan, & Marcogliese, ; Miura, Kuris, & Torchin, ; Nadler & León, ; Pérez‐Ponce de León & Poulin, ).…”

Freshwater parasites as potential barriers to seabird dispersal: Evidence from vagrant booby specimens in western North America

“…specimens, was previously reported from S. leucogaster (Rietschel and Werding 1978). Drepanocephalus is considered a freshwater-obligate parasite (Hernandez-Cruz et al 2017), but future genetic characterization and life cycle studies could uncover a marine connection by second intermediate host fishes (e.g., Beaver 1941, Gonchar and Galaktionov 2020) such as siluriforms (e.g., Alberson et al 2022).…”

“…Previous work has shown that helminths from Caribbean Sula are similar to those from cormorants (Phalacrocoracidae); in particular, the 2 hosts tend to share Drepanocephalus sp. (Flowers et al 2004, Monteiro et al 2011, Sheehan et al 2016, Hernandez-Cruz et al 2017, Sereno-Uribe et al 2019). Overlap in parasite taxa between these 2 bird families may be due to similar prey, similar body sizes (Hoberg and Soudachanh 2021), and phylogenetic relatedness (Hoberg 1996, Nakama 2018, Barrow et al 2019).…”